Detecting changes in the model; php yii framework -

i'm creating audit trail module put in larger system; , i've created table store trail entries , "auditor" want see logged on user, page he/she in, action he/she did, , changes , when...

these want see; audit trail table looks like:

user| timestamp| module name| action| old value| new value| description

i had no problem getting user,

yii::app()->session['username']; 

the page/module , action getting controller's :

$this->module->getname(); $this->action->id; 

my problem lies changes old value new value, edits done user. sort of "sniff" out edits/ changes he/she did literally copying variables , passing through function create log.. how do dynamically?

i sort of want detect if model's properties or attributes has been changed , see changes made detail log...thanks ! sorry, i'm trying hard explain this.

in each model want observe can write afterfind() method, store current db attributes private variable, e.b. _dbvalues. in beforesave() verify current attributes ones in _dbvalues , create audit record if there change.

after have working, can take step further , create behavior it. you'd put private variable, afterfind() , beforesave() method there. can attach behavior many records.